Mercedes-Benz has announced that it is combining the 3.0-liter BlueTEC diesel V-6 in the Euro market S-class with an ECO stop/start function, in an effort to further reduce fuel consumption on the big sedan.

Fitted with this new feature, gas mileage is said to be around 37.9 miles per gallon (6.2 liters per 100 km) combined city/highway. Another result of this has been a further reduction in emissions output, enabling the diesel engine, already fitted with Mercedes' AdBlue urea injection system, to easily clear the tough new Euro 6 smog requirements designed to take effect in 2014.

The ECO Stop/Start system automatically shuts of the engine when the car comes to halt and then immediately re-starts once the driver takes their foot off the brake pedal; however, unlike the old days, when such antics were usually the result of a badly tuned engine that stalled out, all the S350′s other functions, such as HVAC and entertainment features continue to operate while the engine is shut off.